Ask a Teacher

A diode allows electricity to flow in one direction only and blocks the flow in the opposite direction. They may be regarded as one-way valves and they are used in various circuits, usually as a form of protection. There are different types of diode but their basic functions are the same. 

A diode contains two electrodes that act in much the same manner as semiconductors. The positive or p-type is usually the anode and the negative or n-type is the cathode. In other words, the cathode is negatively charged as compared to the anode. If the cathode is charged at the same or very similar voltage to the anode, current will not flow.